Could there be any extension command? I just want the whole command line to include all parameters.
Information similar to the args command line is stored in the PEB (Process Environment Block).
You can find a list of common commands here.
!peb display PEB.
!peb
try vercommand it's a lot easier than that! peb is a good place to get you started: http://windbg.info/doc/1-common-cmds.html#2_general_cmds